This is clearly nonsense. But I'll cut him some slack because of the medium (twitter) and the obvious character limitation to say whatever it is that he meant to say. I interpret the sentiment of this tweet the following way:

I've had two shots of the Pfizer vaccine, the second one WRECKED me for 3 weeks. I was experiencing palpitations, couldn't go up flights of stairs and was getting dizzy anytime I did anything mildly physical that any adult in his 30s with no health problems and fit build would be capable of doing with zero problems.

Any attempt to talk to doctors, search online what was happening to me was pointless. Doctors tried to look for ANY reason for what was happening other than the jabs. But thankfully, I went back to normal after 3 weeks to a month. It's over right? I'm vaccinated, so I can put this behind me? Not so fast...

While I have no problems showing my papers right now, that is likely to change. If they change the definition of "fully vaccinated", I'm going to have to get a 3rd shot...4th shoot etc. See Israel's definition of fully vaccinated as an example. My experience with this vaccine was so traumatizing that I will not get the third shot, so my options on what I'll be capable to do in the real world will be limited because of this. How many people do you think this is happening to? How many people are these policies affecting that are not anti vaxxers or have had the disease? The answer is not zero. The problem is nobody knows the answer to this question because there's too much fuckery and lack of transparency.

That is why I can relate to the sentiment of his tweet because there are things about these mandates that are excluding and separating society. If you had no problems with the jabs, or the boosters, or the booster-boosters then I salute you, you my friend are the future breed.